The present invention refers to a bending machine for sheet metal panels with high edges.
There are known bending machines for sheet metal panels in which the sheet metal panel to be bent, arranged horizontally, is initially squeezed between two bodies, a lower one called xe2x80x9ccounter blade,xe2x80x9d that is fixedly mounted to the base of the machine and operates as a support for the sheet metal panel, and an upper one called xe2x80x9cblank holderxe2x80x9d, that is mobile between a raised position for the introduction of the sheet metal panel and a lowered position in which its resting foot cooperates with the counter blade in order to hold and to keep the same sheet in position. The sheet metal is positioned in such a way that one of its edges, that is destined to be bent, projects horizontally as regards the edges of the counter blade and of the blank holder. The sheet metal is then bent upward by a lower bending blade or downward by an upper bending blade that is situated above said edge. Said upper and lower blades form a pair of bending blades that are usually fixedly mounted to a common support that is displaceable by independent operation which is combinable in vertical and horizontal direction. A machine of this kind has been described, for instance, in the European patent No. 0293964.
In the aforesaid machine the blank holder is hinged onto the back part of the base and it is driven to rotate by hydraulic cylinders whose rods are hinged to the base, and therefore the trajectory described by the blank holder in its lowering and lifting movements is not really rectilinear but is an arc of circumference. This does not allow the bending of sheet metal panels having very high edges since the impact of the blank holder foot with the folded edge would be inevitable during the lifting of the same blank holder.
In view of the state of the art herein described, object of the present invention is to realise a bending machine that allows to bend sheet metal with high edges while preventing any impact of the blank holder foot with the folded edge of the sheet metal panels.
According to the present invention, such object is attained by means of a bending machine for sheet metal panels with high edges comprising a counter blade that is fixedly mounted to a stationary base, a mobile blank holder placed above the counter blade, a turnable support for blank holder that is hinged to said stationary base, first moving means connected with said turnable support so as to control its rotation with respect to said stationary base, characterized in that said blank holder is connected with said turnable support in such a way so as to be able to slide upward and downward with respect to it and second moving means are provided that are suitable to control the sliding of the same blank holder with respect to said turnable support.
Thanks to the present invention a bending machine for sheet metal panels with high edges has been realised that, besides the usual rotary motion, allows the blank holder a substantially rectilinear vertical sliding motion, thus preventing the impact of the same blank holder with the folded edge of the sheet metal panels.